[libcxx-commits] [libcxx] [libc++] Allow the use of extensions in the implementation (PR #79532)

[Nikolas Klauser via libcxx-commits]

philnik777 wrote:

> > We've talked about allowing extensions on [discourse](https://discourse.llvm.org/t/rfc-use-language-extensions-from-future-standards-in-libc/71898/5) and in a libc++ monthly meeting and agreed to test it out in the LLVM 18 release. We've done that with the `tuple` constructor overload set (using conditional `explicit`). Since we haven't heard about any breakages, it seems safe to do.
> 
> Since we don't have a LLVM-18 release yet and presumably not a lot of usage except for users HEAD I feel this conclusion is premature. I really like to wait until after the release and see whether we get breakage before moving forward with this patch.

We've had this in trunk for months now and nobody said anything. rc1 has been out for a week now and nobody said anything. If we caused any non-trivial breakage I'm pretty sure we would have heard about it by now. Everybody wants to start simplifying the code, and I don't think "but maybe" should stop us from doing so by now.

https://github.com/llvm/llvm-project/pull/79532